This invention relates to a method and an apparatus for feeding rod-like material (hereafter "workpiece") to a severing machine, such as a frame saw, a circular cold saw, a band saw or the like. The workpiece which is supported on a machine table and on a feeding device arranged upstream of the machine table as viewed in the direction of feed, is, during the severing operation, clamped in the zone of the cutting plane between at least two jaws which may be opened and closed in a direction transverse to the direction of feed. Between two cutting steps the workpiece is advanced (fed) to the severing machine by means of at least two feed jaws (forming part of the feeding device) which can be opened and closed in a direction transverse to the direction of feed. This cyclical feeding operation which is usually automatically controlled by a preset control device, involves the difficulty in maintaining the final length portion of the workpiece (after the consecutive severing steps) as short as possible in an effort to reduce waste.
According to the prior art devices the clamping shoes are divided or have a notch in the zone of the cutting plane of the saw blade so that they grasp the workpiece at both sides of the cutting plane. The workpiece feed is effected by opening the feed jaws subsequent to a cutting step in order to execute a return motion of the feed jaws to an extent which equals the length of the next feed, while the leading end of the rod is maintained clamped by that part of the clamping jaws which are situated at the feed side (that is, at the upstream side) of the cutting plane. Then the feed jaws again grasp the workpiece and in an open position of the clamping jaws, advance the workpiece to the desired extent. Thereafter, the clamping jaws are closed and the consecutive cutting operation is started. In this arrangement the minimum remaining workpiece length is determined by that portion of the clamping jaws which lie at the upstream side of the cutting plane as well as a minimum length which is just sufficient to be still securely grasped by the feed jaws.
In order to reduce the residual length (waste length) of the workpiece, it has been known to provide the feed-side part of the clamping jaws with a recess into which the feed jaws may telescope to arrive closer to the cutting plane. Even in such an arrangement, the waste length of the workpiece is substantial and may be many times greater than the programmed length to be severed, so that waste lengths are obtained from which at least one more programmed length portion could have been severed.